1. Field of the Invention
The present invention pertains to the art of cooking appliances and, more particularly, to a cooking appliance including a convection cooking system having a controlled exhaust outlet that establishes a pressure differential within the convection cooking system causing fresh air to be drawn into the appliance.
2. Discussion of the Prior Art
In the art of cooking, it is common to incorporate a convection cooking system in an oven for performing a particular cooking process. Typically, convection cooking systems include a fan for establishing a heated airflow by passing oven gases over a heating element prior to re-introducing the airflow into the oven. In addition to the heated airflow, provisions must be made to exhaust a portion of the oven gases from the oven. Therefore, the convection cooking system must include structure designed to ventilate or evacuate exhaust gases from the appliance.
There are two key components associated with the design of oven ventilation systems. The primary concern is the build-up of gases which include carbon monoxide (CO) and carbon dioxide (CO2) within the oven. If the gases are evacuated from the oven too quickly, the efficiency of the cooking process, as well as oven pre-heat time, will be reduced. On the other hand, if the gases are evacuated too slowly, a large smoke cloud could pour forth into the kitchen after completion of a closed door cooking process and, in particular, a broil operation. Thus, the ventilation system must be designed to handle the dissipation of the smoke cloud, as well as to promote overall oven efficiency.
The second key component in the design of an oven ventilation system is controlling oven gas exhaust temperature. That is, the temperature of the exhausting oven gases should not be too hot or too low. For example, permitting the exhaust gas temperature to be too low will undesirably develop condensation of the food effluents and steam as the exhaust gases exit the oven.
Several attempts have been made to develop better ventilation systems for ovens. In general, such systems require extensive ducting, catalyst reactors, outlet baffles or the like. While each is effective to a degree, all require the use of additional, expensive components or systems which add to the overall cost and complexity of the oven. In the highly competitive field of cooking appliances, it is important to deliver a product at a low cost, while maintaining quality and efficiency standards. Therefore, despite the existence of various oven ventilation systems in the prior art, there still exists a need for a low cost, relatively simple oven ventilation system that provides the proper balance between exhaust gas temperature and exit velocity.